Smart heating system HA

[Hellis81]

Just for the esthetics, you could keep the termostat or put a blank plate over the hole and on the boiler find the terminals from the termostat and place the relay there Instead.
But that’s up to you.

@MarcelloTT

Shelly 1 is fine, but it’s just a shame it’s Wi-Fi and not Zigbee.

Zigbee relay? (dry contact)

Is there any Zigbee relay module available internationally (Aliexpress, Banggood)? I’m looking for 2/4 relays module which is not wifi but Zigbee. It is very important not to switch Line but use dry contacts. It can be a module behind a wall switch but or something like Sonoff ch4 pro. The most important not to add 110V or 230V on the output but contact 2 pins/wires.